SUMMARY Three groups of patients who had suffered head injury were compared with matched control subjects on reaction time (RT) tasks. Group I consisted of outpatients previously hospitalised for head injury ofwide ranging degrees of severity, assessed at varying intervals after injury. Group II was composed of non-hospitalised mildly concussed patients. Group III was made up of head injured patients of varying degrees of severity assessed 7-10 months after initial hospitalisation for their injury. The reaction time tests were graded in difficulty, from a simple RT response to a complex choice RT test. In addition, subjects were compared in their ability to ignore redundant information during one of the choice RT tests. The findings indicate that traumatic brain injury causes slower information processing, deficits in divided attention, an impairment of focused attention, and inconsistency of performance.Reaction time (RT) tests have consistently revealed slowness ofinformation processing, a deficit in divided attention after head injury.' In this study, we addressed four specific issues concerning the effects of head injury on reaction time.The question of fatigue was examined by using the same simple RT test at the beginning and end of experimental sessions to see if head injured patients and normal control subjects changed their performance differently across the session.A second question addressed the nature of the attentional deficit. While "There can be no controversy... about the presence of DADs [divided attention deficit] in head injury",2 there has been less success in identifying a specific impairment in focused attention.< Focused attention is tested by evaluating the ability to ignore distracting stimuli. A selective involvement of frontal lobe areas has been suggested in head injury7"'1 and deficits in focused attention using

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Loss of spinal alignment can lead to neurological compromise in individuals with unstable spine injuries. We compared the ability of the Roto-Rest bed and the Stryker frame to immobilize an unstable cervical and lumbar segment in a cadaver. The Roto-Rest bed was superior to the Stryker frame in the immobilization of both cervical and lumbar fractures.

ABSTRACT:The effects of traumatic brain injury (TBI) and aging were compared on tests of simple and complex reaction time (RT). Simple RT was not significantly affected by aging or TBI. TBI patients, however, tended to be slower on Simple RT tasks, and had a larger standard deviation. Individuals over age 60 and patients of any age with TBI demonstrated slower RT with choice RT tests. In addition, both groups (those over 60 and TBI patients) were less able than other groups to inhibit the processing of redundant information. For the TBI patients, this occurred primarily on reassessment. These results suggest that the deficit in both aging and TBI is not only a generalized neuronal slowing but a more specific impairment in attentional control processes, exhibited as a deficit in focused attention. RESUME: Lesion cerebrate traumatique, vieillissement et temps de reaction Nous avons compare les effets de lesions cerfibrales traumatiques (LCT) et du vieillissement par des epreuves du temps de reaction (TR) simple et complexe. Le TR simple n'etait pas affecte de facon significative par le vieillissement ou par une LCT. Cependant, les patients avec LCT avaient tendance a etre plus lents dans les epreuves de TR simple et avaient un ecart type plus considerable. Les individus au-dessus de 60 ans ainsi que les patients de tous ages avec LCT manifestaient un TR plus lent dans certaines epreuves TR. De plus, les deux groupes (les individus de plus de 60 ans et les patients) etaient moins aptes que les autres groupes a inhiber le traitement d'informations redondantes. Dans le cas des patients avec LCT, ceci survenait surtout lors de la devaluation. Ces resultats suggerent que le deficit dans le vieillissement et la LCT n'est pas seulement un ralentissement neuronal generalise, mais aussi une alteration plus specifique du processus de controle de I'attention, manifeste par un deficit de l'attention focalisee.Can. J. Neurol. Sci. 1989; 16:161-167 Aging and traumatic brain injury (TBI) appear to have some similar effects on complex information processing. With advancing age there is a behavioral slowing, the degree of slowing being a function of task complexity.1 " 3 TBI also causes slowing of reaction time (RT).4 " 6 The slowing varies with task complexity and complex choice RT best reflects the severity of TBI 7 -". Gronwall, 12 describing the performance of patients with mild head injury, suggested that "these difficulties are similar to those a 65-year man would have if suddenly confronted with the work schedule he had coped with at 25" (p. 372).There appear to be at least broad similarities between aging and TBI in their effect on the brain. Severe TBI results in widespread brain damage;13 -14 aging also causes diffuse loss of neurons.15 -16 Both aging and TBI may cause focal frontal lobe dysfunction. The frontal lobes are particularly sensitive to damage by the inertial effects of TBI.1317 " 20 Neuropsychological tests 21 " 23 and blood flow studies 24 both suggest frontal lobe dysfunction with increasing age, althoug...

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